Agent and mineral oil lubricant compositions containing the same



Pawnee nee it, was I AGENT AND WERAIL OH; LUIBRIGAN'E COM- 1 POSITIONS CONTAINING THE SAME Herschel G. Smith, Wallingtord, and Troy L. Cantrell, Lansdowne, Pa, assignors to Gulf i] Corporation, Pittsburgh, Pa, a corporation oi Pennsylvania "at Drawing. Application March 2c, 1947,

Serial No. 736,618

I This invention relates to improvement agents I and mineral oil lubricant compositions containing the same and, more particularly,- it is concerned with improvement agents which confer improved anti-oxidant, corrosion-inhibiting and pressure-carrying properties on mineral oil lubricants.

18 Claims. (El. 2524 6.$)

' lubricants which confers excellent antioxidant,

It is recognized in the art that mineral oil lubricants are readily oxidized under service conditions thereby reducing the service life of internal combustion engines and steam turbines. A concomitant eflect is corrosion of bearing surfaces. These problems become particularly acute when a highly refined paramnic base mineral oil is employed as the lubricant.

In the lubrication of internal combustion engines of all types, particularly when severe operating conditions are encountered, mineral lubricating oils frequently prove unsatisfactory because they tend to deposit varnish, gum and v sludge on the engine surfaces, such as the cylinder walls, pistons and rings, and" also to induce corrosion of bearing materials thereby causing failure oi the engine. These problems have become increasingly serious because of'the trend toward substances tend to increase ring sticking and accelerate the formation of further deposits on piston surfaces and in fixed parts of the combustion chamber. The sludges formed in the crank case of the engine increase the rate of corrosion of bearing surfaces, especially of bearing alloys of I the types now in use.

In steam turbines, the corrosion problem is particularly acute because of the presence of water in the mineral oillubricant and in addition to bearing corrosion, rusting may also be encountered.

It is an object of this invention, therefore, to prepare an improvement agent which will obviate the oxidation and corrosion dimculties encountered in the use of mineral oil lubricants.

It is a further object of this invention to provide improved mineral oil lubricant compositions which are stable in storage and use and in which oxidation and corrosion efiects are materially inhibited.

It is also an object of this invention to provide corrosion-inhibiting and pressure-carrying properties on mineral oil lubricants. Such improvement agent is prepared by heating an essentially paramnic base lubricating oil with anhydrous aluminum chloride, removing aluminum chloride from thereaction product and reacting said product with phosphorous pentasulfide at an elevated temperature to incorporate phosphorus and sulfur' therein.

The objects of the present invention are accomplished by providing an improvement agent for mineral oil lubricants by reacting an essentially parafinic base lubricating oil with phosphorus pentasulfide in thepresence of a surface active silica-containing solid catalyst to incorporate phosphorus and sulfur in said lubricating oil, and recovering the reaction product. The reaction product so obtained is an excellent lightvcolored improvement agent for mineral oil lubricant compositions, which is remarkably effective for inhibiting oxidation and corrosion and which in addition confers excellent pressure-carrying properties. Such improvement agents, as well as the mineral oil lubricant compositions containing them, are believed to be novel and are considered parts of our invention.

In one aspect, the present invention is an improvement over the invention disclosed in our above-identified copending application. As shown in said application, if the treatment of an essentially parafinic base lubricating oil stock with anhydrous aluminum chloride is omitted prior to reacting the oil with phosphorus pentasulfide, there is obtained a black sludge-like product which is poorly soluble in mineral lubricating oils and which imparts such a degree of color to mineral oil lubricant compositions as to render'them unmarketable. However, in accordance with the present invention, the aluminum chloride treatment may be omitted without obtaining the abovedescribed black sludge-like product, provided that the reaction of the essentially paraflinic base a lubricating oil with phosphorus pentasulfide takes place in the presence of a surface active silicacontaining solid catalyst. It is still necessary to employ an essentially parafinic base lubricating oil as the initial material, however, because other hydrocarbon materials produce the black, sludgelike, difflcultly soluble product regardless of the auaese.

fects of the surface active silica-containing solid catalyst on the reaction arenot fully understood. However, the use of such a catalyst is essential for the practice of our invention, since, if the catalyst is omitted, the advantageous results of our invention are not obtained. In order to obtain the results of our invention, therefore, it is necessary (1) to employ an essentially paramnic base lubri cating oil, and (2) to conduct the reaction with phosphorus pentasulfide in the presence of a surface active silica-containing solid catalyst.

The essentially parafdnic base lubricating oil used as a starting material in accordance with our invention may be derived from any parafllnic crude, such as Pennsylvania, Mid-continent or other parafilnic base crudes. The lubricating oil is manufactured from such crudes in accordance with conventional methods and may be refined reacted with phosphorus pentasulfide in the presence of a surface active silica-containing solid catalyst. The products so obtained have a color which is lighter than that obtained when the aluminum chloride treatment is omitted. If it is desired to treat the essentially para'filnic base lubricating oil with aluminum chloride, such treatmentis accomplished as described in our copendingapplication. Briefly, such treatment comprises heating the essentially paraillnic base lubricating oil with from 1 to 20 per cent by weight of anhydrous aluminum chloride at a temperature of from 150 to 300 F. while vigorously agitating. The time of treatment may vary in accordance with the amount of aluminum chloride used and the temperature of treatment, longer times being required with less aluminum chloride and lower temperatures. In general, the treatment will becompleted after 4 or 5 hours. After the treatment is completed, agitation is stopped and a sludge containing most of the aluminum chloride settles out from the main body of the oil and is drawn oil. The supernatant body of the treated oil may contain further quantities of aluminum chloride finely dispersed therethrough and, in order to insure the removal of all aluminum chloride from the treated oil, agitation with an adsorbent clay followed by filtration may be employed. At the higher temperatures of treatment with aluminum chloride some conversion of the parafilnic base oil to lower boiling products may take place and, although such conversion is slight, the product maybe topped, if desired; that is, distilled to remove the lower boiling products overhead and to recover as'a residue the bulk of the aluminum chloride treated oil having a minimum initial boiling point in the range 490 to 530 F.-

The reaction of the essentially paraflinic base lubricating oil, whether or not treated with aluminum chloride, with phosphorus pentasulfide in the presence of the catalyst is accomplished by adding from 2 to 20 per cent by weight of Pisa,-

preferably from 5 to per cent, to the essentially parafllnic base lubricating oil and heating with agitation at a temperature in the range from 300 F. to a maximum reaction temperature below the temperature where cracking of the oil, that is,

pyrolytic decomposition of the oil begins. Generally the minimum cracking temperature of the oil will vary between 490 to 530 F. depending upon the particular oil used. The surface-active 5 silica-containing solid catalyst is employed in an amount of from 2 to 25 per cent by weight of the oil charged, and preferably in an amount of 10 percent by weight. Larger amounts than 10 per cent are ordinarily not necessary, but larger 10 amounts will produce a product having a lighter color. During the course of the reaction, hydrogen sulfide is evolved and phosphorus and sulfur become incorporated in the oil. When the evolution of hydrogen sulfide has nearly ceased, the temperature of the reaction mixture may be increased within the maximum temperature disclosed above, say to about 500 F., for completion of the reaction. The mixture is then filtered to remove the catalyst. The products so obtained are excellent improvement agents for mineral oil lubricants.

The surface active silica-containing solid catalysts may comprise activated clays, silica-alumina cracking catalysts and the like. Thus, activated clays, that is, natural clays such as bentonite, smectite, floridin, fuller's earth and the like which have been treated with acid, as described in U. S.

Patent No. 1,898,165, for example, may be advantageously employed. Synthetic silica-alumina 3 catalysts of the type used for the cracking of hydrocarbon oils and which are described in U. 8. Patent No. 2,078,945 and U. S. Patent No. 2,283,173, for example, may also be employed. Activated silica gel is also suitable. As may be as seen, the term "surface active silica-containing solid catalyst comprises a wide variety of materials, the predominant characteristic of which is the presence of silica in a surface active, that is, activatedform.

o The following examples illustrate the preparation of our new improvement agents:

Example I Eight thousand five hundred fifty parts by a weight of an SAE grade paraiilnic lubricating oil were placed into a reaction vessel equipped with an agitator and means for heating and cooling. Then 450 parts by weight of phosphorus pentasulfide and 900 parts by weight of an activated clay catalyst were added with stirring at a temperature of 400 F'. The temperature was held at 400 F. until evolution of hydrogen sulfide had nearly ceased, and then the temperature was raised to 500 F. and held at that point for 2 hours with agitation. The reaction with the Pass from the time of its addition to the completion of the reaction took 8 hours. The product was then cooled and filtered. The product had the following properties:

Ten thousand parts by weight of a solvent treated dewaxed lubricating oil stock, 1000 parts by weight of phosphorus pentasulfide and 1000 parts by weight of an activated clay catalyst were placed inra reaction vessel. The mixture was 5 maintained at 400 F. with stirring until the evolution of hydrogen sulfide had subsided. The temperature was then raised to 500 F. to complete the reaction. The product was hen cooled Example III Ninety-five parts by weight of a paraiflnic base lubricating oil, 5 parts by weight of Past and 5 parts by weight of an activated clay catalyst were reacted under the conditions set forth in Example I. The filtered product had the following properties:

Example IV Ninety-five parts by weight of a paramnic base lubricating oil which had been treated with aluminum chloride as disclosed hereinabove, 5 parts' by weight of P235 and 20 parts by weight of an activated clay catalyst were reacted under the conditions set forth in Example I. The'filtere product had the following properties:

Gravity, "API 28.0 Viscosity, SUV:

Color, NPA 3.0 Sulfur, percent 1.67 Phosphorus, percent 1.10 Neutralization No. 8.0

The phosphorus pentasulfide reaction products obtained in accordancewith the preceding examples are excellent improvement agents foamineral oil lubricant compositions. They are lightcolored and readily soluble in all types of mineral oils, that is, parafiinic, naphthenic or mixed. base mineral oils and, as a matter of fact, can be blended with mineral oils in proportions as high as 50 per cent by weight or higher. This excellent solubility of our new improvement agents enables the preparation of concentrated solutions, which may then be diluted down to the proportion desired in the final mineral oil lubricant composition. As stated, our new improvement agents confer excellent pressure-carrying, antioxidant and corrosion-inhibiting properties on the mineral lubricating oils with which they are incorporated. For these purposes, our new improvement agents are generally added to'mineral oils in minor amounts, say from 0.1 per cent to 20 per cent by weight of the mineral oil, sumcient to confer improved pressure-carrying, antioxidant and corrosion inhibiting properties on'the mineral lubricating oils with which they are incorporated; When our new improvement agents are to be used for their antioxidant and corrosioninhibiting effects, small proportions as low as 0.1 per cent by weight are sufficient to eflect the imprcvement. When extreme pressure properties are to be conferred on a lubricating oil, higher proportions, as high as 20 per cent, may conveniently be used.

properties of the. improved and unimproved motor oils were as follows:

Unimproved. Improved Motor Oil Motor Oil Gravity, API 20.0 29. 1 viscoslltg SUV: 100 F. 620 520 Color, f'A 1.15 1. 76 Oxidation and Bearing Corrosion Test Method 257, Gull:

Duration of Test, Hr 48 48 011 Bath Tem 347 847 Air Rate, Cc./ r 2,000 2,000 Quantity oi Oil, Oc 300 300 Bearing T (id-Ag Cd-Ag Wt. C ange- Grams. J 0. 1744 0. 047 Per cent -0 00 -0. 01

Example VI The following examples illustrate the use of our new improvement agents to obtain improved mineral oil lubricant compositions:

Example V An excellent motor oil, SAE 30 grade, was prepared by blending 1 part by weight of the improvement agent prepared in accordance with Example I with 99 parts by-weight of a highly refined parailinic 'SAE 30 grade motor oil. The

properties of the unimproved and improved motor oils were as follows:

Unimproved Improved Motor Oil Motor Oil Gravity, "API 29. 0 29. l Viscosity SUV: 100 F. 520 520 Color, NiA l. 2. 2s Oxidation and Bearing Corrosion Test Method 257, Gull:

Duration of Test, Hr 48 48 Oil Bath Temperature, T. 347 347 Air Rate, CcJHr 2,000 2,000 Quantity of Oil, Cc 300 300 Bearing Type Cd-Ag Crl-Ag Wt. Change- Grams -0. 1744 -0. 052 Percent -0.06 0.01

Example VII An SAE 30 grade motor oil was treated with 1 per cent by weight of the improvement agent prepared in accordance with Example IV. The properties of the unimproved and improved motor oils were as follows:

Example VIII An improved turbine oil was prepared by blending 0.3 parts by weight of the improvement agent prepared in accordance with Example I and 99.7 parts by weight of a well refined turbine oil base. The properties of the improved and unimproved turbine oils are as follows:

Impr ved Turbine Oil Gravity API viscosilt BUV2130 r 2. 190. Color, is a Oxidation and Bearing Corrosion Test Method 257 Gull Duration oi Test, Hr 4B 48 Oil Bath Temperature: F 347 347 Air Rate, CcJHr 2,000 2,000 uantity oi Oil, Cc- 300 son em 6 are Wei t an eram-5..

g 8 Per cent 0.96 0. i

Corrosion Test, ASTM Dildo-4.4T: Distilled Water. Steel Rd rust: passes Example IX A lubricating oil having excellent extreme pressure properties was prepared by blending parts by weight of the improvement agent made according to Example I and 85 parts by weight of a highly refined motor oil. A comparison of the properties of the improved lubricant and the base lubricant follows:

The "Oxidation and Bearing Corrosion Test, Method 257, Gulf," referred to in the foregoing examples, is conducted as follows:

An alloy bearing shell of certain commonly used standard dimensions is submerged in 300 cc. of

the oil or oil composition to be tested in a 400 cc; heated in a thermostatically Pyrex beaker and controlled oil bath to 347 F. Air is then bubbled through the oil in contact with the bearing shell at a rate of 2000 cc. per hour. At the end of 48 hours, the loss of weight and condition of the bearing shell are determined, the bearing shell being washed free of oil and dried before weighlng. When determining the effectiveness of various improvement agents, the usual procedure is to run a blank test simultaneously with the oil composition being tested, employing for that purpose a sample of'the untreated oil. In this test it is advantageous to employ commercial bearing shells. These shells comprise a suitable metal backing faced with the alloy bearing metal. In this way the actual bearing face is subjected to severe deterioration conditions. By comparison of the results of such tests with actual service tests, we have found them. to be in substantial agreement as to suitability of particular lubricants.

. As shown in the above examples, the addition of our new improvement agents to mineral oil lubricant compositions confers excellent pressure-carrying, antioxidant and corrosion-inhibiting properties. At the same time the compositions so obtained are stable in storage and use and have a color which is substantially unaflected by the addition of the improvement agent.

While we have shown in the examples the preparation of compounded lubricating oils, our invention is not limited thereto but comprises all mineral oil lubricant compositions containing our nfiw improvement agents, such as greases and the 11 e.

1. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially paraffinic base lubricating oil with phosphorus pentasulfide in the presence of a surface active silica-containing solid catalyst at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of said lubricating oil to incorporate phosphorus and sulfur in said lubricating oil, and recovering the reaction product.

2. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially parafiinic base lubricating oil with from 2 to 20 per cent by weight of phosphorus pentasulflde in the presence of from 2 to 25 per cent by weight of a surface active silicaeontaining solid catalyst at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of said lubricating oil to incorporate phosphorus and sulfur in said lubricating oil, and recovering the reaction product.

3. The process of claim 2, wherein the amount of phosphorus pentasulflde is from 5 to 10 per cent.

4. The process of claim 2, wherein the catalyst is an activated clay catalyst.

5. The process of claim 2, wherein the catalyst is a cracking catalyst of the silica-alumina type.

6. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially parafflnic base lubricating oil with from 5 to 10 per cent by weight of phosphorus pentasulflde in the presence of 10 per cent by weight of a surface active silica-contain ing solid catalyst at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of said lubricating oil to incorporate phosphorus and sulfur in said lubricating oil, recovering the reaction product and dissolving it in a mineral lubricating oil.

7. The process of preparing an improvement agent for mineral oil lubricants which comprises heating an essentially paraflinic base lubrication oil with anhydrous aluminum chloride at a temperature of from 150 to 300 F., removing aluminum chloride from the reaction product, beating said product with phosphorus pentasulfide in the presence 'of a surface active silica-containing solid catalyst at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of the aluminum chloride treated oil to incorporate phosphorus and sulfur therein, and recovering the reaction product.

- 8. The process of preparing an improvernent agent for mineral oil lubricants which comprises heating an essentially paraflinic base lubricating oil with from 1 to 20 per cent by weight of anhydrous aluminum chloride at a temperature of from to 300 F., removing aluminum chloride from the reaction product, heating said product with from 2 to 20 per cent by weight of phosphorus pentasuliide in the presence of from 2 to 25 per cent by weight of a surface active silicacontaining solid catalyst at a temperature of from 300 F. to a maximum temperature below the minimum cracking temperature of the aluminum chloride treated oil to incorporate phosphorus and sulfur therein, and recovering the reaction product.

9. The product obtained by the process of claim 1.

10. The product obtained by the process of claim 2.

11. An improvement agent for mineral oil lubricants obtained in accordance with the process of claim 6.

12. The product obtained by the process of claim 7.

13. The product obtained by the process of claim 8. v

14.'A lubricant composition comprising amajor amount of a mineral lubricating oil and a minor amount, suflicient to confer improved pressure-carrying, antioxidant and corrosion-inhibiting properties on the composition, of the product obtained by the process of claiml.

15. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, from 0.1 to 20 per cent by weight, 01' the product obtained by the process of claim 2. I

16. A lubricant composition comprising a major amount of a mineral lubricating oil and a minor amount, suflicient to confer improved pressurecarrying, antioxidant and corrosion-inhibiting r 10 I properties on the composition, of the product ob. tained by the process oi claim 7.

17. A lubricant composition comprisinga major,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 20 Number Name Date 2,309,718 Thacker Feb. 2, 1943 2,316,082 Loane Apr. 6, 1943 2,315,529 Kelso Apr. 6, 1943 2,816,090 Kelso et al. Apr. 8, 1943- Mixon Jan; 16, 1945 I 

